Biosecurity  Value chain for animal-derived food
Biosecurity:
Value chain for animal-derived food
Author: Dr Mary-Louise Penrith
Licensed under a Creative Commons Attribution license.
TABLE OF CONTENTS
Table of contents ...........................................................................................................1
Introduction ....................................................................................................................2
Definitions ......................................................................................................................2
Farming systems ...........................................................................................................2
Biosecurity in farming systems ...............................................................................................2
Transport ........................................................................................................................6
Biosecurity during transport ....................................................................................................6
Processing .....................................................................................................................6
Biosecurity during processing .................................................................................................6
Hazard Analysis Critical Points (HACCP) ....................................................................6
References .....................................................................................................................8
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Biosecurity  Value chain for animal-derived food
INTRODUCTION
The concept of assuring the safety of food derived from animals from the moment of birth of the animal until
the products derived from it reach the consumer dictates the need for biosecurity implementation throughout
the value chain. This is often expressed as assurance ‘from stable to table’ or ‘from farm to fork’. However,
before animal-derived food reaches the table or the fork there is generally a transfer of responsibility for its
safety from the veterinary to the human health authorities. Thus veterinary responsibility usually ends when
the product leaves the abattoir, the dairy or the egg production unit, but the ‘one health’ concept requires a
level of communication between the veterinary and medical authorities that will ensure sufficient knowledge
on both sides of possible hazards of concern. The great majority of the hazards involved are pathogenic
micro-organisms but can include residues of biological substances administered to the animals (hormones,
antimicrobials) (See the modules on Veterinary public health and food safety: Meat hygiene) -. Measures are
of course also required to prevent hazardous non-biological substances like heavy metals and toxic
chemicals from entering the human or animal food chain, and some of these are not easily separated from
the prevention of biological hazards. However, the focus in this module is on the prevention of infectious
disease-causing organisms being present in the final product when it leaves the processing plant, i.e. the
part of the value chain for which veterinarians is responsible. In 2011 the Food and Agriculture Organization
of the United Nations (FAO) provided guidelines on managing animal health across the value chain by
identifying risks and instituting measures to mitigate them. This is effectively the HACCP approach that is
used to assure food safety and is a great step forward towards integrating animal health management and
food safety measures.
DEFINITIONS
Definitions for biosecurity that have been used are:

Security from transmission of infectious diseases, parasites and pests (Saunders Medical Dictionary)

Biosecurity means protection from the risks posed by organisms to the economy, environment and
people’s health, through exclusion, eradication and control (Biosecurity New Zealand)

Biosecurity means by definition to create an environment where infectious diseases are removed and
prevented from spreading (Infovets) (URL: http://www.infovets.com/styles/?page=home.htm)
FARMING SYSTEMS
Biosecurity in farming systems
The application of biosecurity measures in the production unit is of cardinal importance to ensure that only
healthy animals leave the farm. Essentially, on farm biosecurity means the construction of “barriers” between
the animal and the pathogen. These “barriers” may be physical, e.g. buildings and screens to exclude
vectors; chemical, e.g. disinfectants and prophylactic medicines and pesticides; or biological, e.g. vaccines.
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Biosecurity  Value chain for animal-derived food
The nature of the “barriers” and how they are implemented depends on the species and the farming system.
In order to determine where “barriers” are required, it is necessary to identify the points at which the risks are
highest and decide upon the best way to mitigate them, given the type of husbandry system involved.
Stringent biosecurity measures such as showering in and out of the facility and vector exclusion can be
applied only in indoor systems such as intensive commercial pig and poultry units.
The implementation of on-farm biosecurity measures is the daily responsibility of the producer, but it is up to
the veterinary authorities, either through producer organisations or when they consult on farms, to provide
the necessary guidelines. These will vary according to the production system and are generally far more
stringent for large, intensive indoor farming systems than for animals raised extensively on pasture. This is
because intensive farming systems are prone to a build-up of pathogens due to large numbers of animals
being kept at close quarters.
The first step in designing “barriers” between animals and pathogens is to identify potential sources of
pathogens. These include other animals, humans, feed, water, aerosols, invertebrate vectors and
contaminated objects (fomites). Other animals are generally the most important source of pathogens and
these can include introduced animals of the same species, animals of other species that come into contact
with the farmed animals (e.g. birds, rodents, carnivores, wildlife, other species of livestock), and animals
within the herd. For example, animals in the herd, in particular adults, may carry potential pathogens that are
commensal in them due to their immunity but can cause disease in other animals, for example the very
young, or naïve new entrants into the herd.
Measures used to prevent pathogens from being brought into a herd from outside sources (external
biosecurity measures) include:

Restricted access to the premises where the animals are kept

Hygienic measures to ensure that people who need to enter the premises do not bring in pathogens and
strict control/decontamination of materials brought onto the farm

Keeping a closed herd

Introduction of animals only from herds of known health status

Quarantine of newly introduced animals

Legal requirements for a minimum distance between farms

Measures to keep out rodents, birds, carnivores, other livestock; strict separation between domestic
livestock and wildlife

Strict control over feed; no swill feeding; ensuring that feed and feed sources are wholesome and free
from contaminants from manufacture through delivery and storage to consumption

Exclusion of vectors (e.g. insect-proof stables, barns).
It is evident that some of the measures are more practical and easy to implement than others, depending on
the animals and how they are kept.
Restricting access is supported by adequate fencing and locked gates, an office close to the gate where
visitors must report, and implementing a strict ‘No visitors’ policy that is understood and adhered to by
workers and managers. In intensive farming systems it is advisable to design the farm in such a way that
feed deliveries and loading of livestock take place on the periphery of the farm so that vehicles that do not
belong to the farm do not enter the premises. On extensive farms, although security measures are often in
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Biosecurity  Value chain for animal-derived food
place to prevent stock theft, these may be breached and it must be borne in mind that stock theft is one way
in which diseases may be spread.
Hygienic measures to prevent people and fomites from bringing in pathogens must be adequate or they are
a waste of time and money. For example, disinfection without prior cleansing and removal of solid material,
e.g. providing disinfectant foot baths without a means to cleanse the footwear first, is a waster of resources
and dangerous because there is an illusion that the herd is protected. It is far safer and probably in the end
more cost effective to supply footwear to workers and essential visitors to ensure that footwear from outside
does not enter the facility. In intensive indoor production systems shower-in facilities with a change of
clothing may be available. This is particularly to be recommended in areas where serious diseases are
endemic, during outbreaks, and between barns if the same workers are working with different age/production
stage groups. Whether this level of protection is required will be determined by an assessment of the risk of
introduction of pathogens that will only be eliminated by showering and a complete change of clothes. Most
pathogens carried on the person will be prevented from being transmitted to the animals by a change of
footwear and changing or covering outer clothing, covering the hair and thoroughly washing hands with
disinfectant soap before handling animals. Equipment used in handling and treating animals can be a potent
source of infection, particularly restraint devices that enter the nose or mouth of the animals and used
needles that may be contaminated with blood. It is the responsibility of the veterinarian to ensure that any
veterinary equipment has been meticulously cleaned and disinfected or has been replaced before being
used on a new herd. On the farm, it is preferable to have separate sets of equipment for different houses,
camps and/or age groups.
Keeping a closed herd will depend on the species and size of the herd; the particular problems of
implementing biosecurity measures in small herds will be discussed in more detail below. The use of artificial
insemination in species where this is available reduces the risk of genitally transmitted pathogens provided
the source of semen is reliable and enables genetic improvement without the introduction of new animals.
Many herds will need or want to introduce new animals either for reasons of genetic improvement or simply
because they cannot produce enough replacement animals themselves. The animals should always be
sourced from herds of reliably known good health status and should be accompanied by a veterinary
certificate. This should eliminate the need for strict quarantine in a completely separate facility at a distance
of at least 400 metres from the rest of the herd and with its own dedicated attendants, which is generally
impractical except on the largest farms. It is, however, advisable to keep new introductions in a separate pen
or camp for a period of 3 – 4 weeks to settle down in the new environment and if possible for them to be
cared for by a worker who is not at the same time working in the rest of the herd. Animals introduced into a
new environment are usually stressed and may shed pathogens that they were not known to be carrying,
and this will be exacerbated by immediately mixing them with other animals.
There are many recommendations and in some countries there is legislation about the distance between
farms, particularly intensive farms where large concentrations of aerosols may be produced. It is obviously
not possible to move existing farms further apart, and if farms are closer than the recommended distance,
which varies from 500 metres to 4 km, the risk has to be accepted and mitigated as far as possible. Hepa
filters are used to exclude pathogens in some climate-controlled barns but most farmed animals have some
exposure to the open air and will need to be vaccinated against air-borne diseases if these are deemed to
pose a high level of risk.
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Biosecurity  Value chain for animal-derived food
Excluding other species that may carry pathogens is often difficult and again, the risk that they pose needs to
be assessed in order to determine the necessary measures. Measures such as ensuring that the feed is
stored in rodent- and bird-proof rooms or containers and that spilled and leftover feed is kept to a minimum
reduces the attraction, and more drastic measures can be instituted if they appear to be necessary. Cats,
which are a source of Toxoplasma gondii, are attracted to facilities where there are rodents and can be
helpful in rodent control; excluding them from the feed store will reduce the possibility of their infecting the
livestock.
Feed can be a potent source of pathogens. Catering swill, which is often fed to pigs, especially on smaller
farms, has often been incriminated in the introduction of serious diseases such as foot-and-mouth disease,
classical and African swine fever. Fodder or grain contaminated by faeces or the dead bodies of rodents,
birds or other animals may be the source of infections by salmonellae and clostridia and various other
pathogens. Mycotoxins can cause serious problems and the feed may not be obviously mouldy for them to
be present. Feed produced/sourced off farm must be of guaranteed high quality and must be stored in such
a way that it does not become contaminated with bacteria or fungi after it has been delivered.
With the exception of indoor systems where screened windows and doors may be feasible or which are fully
climate controlled, vector exclusion is often impossible. Vectors that are only active during particular periods,
e.g. Culicoides spp., can be kept at bay by stabling animals in insect-proof stables from dusk to dawn when
they are active. The use of fly repellents is also recommended. Control of vectors that remain on the host for
some time, e.g. ticks, mites and lice is achieved by the use of pesticides aimed at breaking the life cycle of
the parasite. Similarly, pesticides treated cattle can be used as targets to control tsetse flies. In order to
minimise product resistance development and adverse environmental effects (pollution and loss of
biodiversity) it is recommended that the products should be used strategically and that in endemic areas
animals should be allowed to maintain their immunity to the pathogens.
Measures to prevent transmission of pathogens within the herd include stringent hygienic measures,
separation of age groups, and all-in all-out systems. These measures are usually supported by vaccination,
sometimes by prophylactic medication, and sometimes by testing and treatment or culling in order to
eliminate certain pathogens.
The application of biosecurity measures to non-intensive farming systems can be challenging. In freeranging systems the main sources of infection are contact with other herds, contact with wildlife and vectorborne diseases, as well as transmission of highly contagious diseases like foot-and-mouth disease and
African swine fever by contaminated humans and equipment. There is also a risk of diseases caused by
pathogens that can survive outside the host, for example in soil, like anthrax. For scavenging animals like
pigs there is the danger of ingesting infected material from carcasses and other waste. Biosecurity measures
include the use of parasiticides and fly repellents, vaccination, and separation of livestock from wildlife and
from other herds and minimising unauthorised access to animals. The only effective way to prevent
scavenging animals from accessing unsuitable and possibly infectious material is to confine them, which is
often not attractive to producers because it requires investment. Incentives include better protection for the
animals from accidents and predators, better control of health and production, and elimination of diseases
such as porcine cysticercosis and African swine fever. This, however, may only be attractive if it will ensure
access to better markets and greater profitability for the enterprise so that the additional costs of caring for
the animals will be covered.
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Biosecurity  Value chain for animal-derived food
In addition to food derived from domestic animals raised on farms, there are niche markets such as venison
derived from game animals. Even if these are raised on ranches, it is impossible to exercise the same level
of control over their health, and they are usually harvested by hunting. Feasible biosecurity measures include
only introducing new animals that either have reliable health certification or after a period of quarantine and
observation in a dedicated camp, exercising parasite control according to the methods available for nondomestic animals, ensuring that the cause of death of any of the animals is established and control
measures are put in place if necessary, and avoiding over-stocking and overgrazing.
TRANSPORT
Biosecurity during transport
Most food animals are moved off the farm to an abattoir, and sometimes to other intermediate destinations
such as out-grower sites or feedlots, so maintaining freedom from pathogens during transport is an issue.
The most important source of pathogens during transport would be the part of the vehicle in which the
animals travel, or for small species such as chickens the containers in which they travel. Protocols have
been developed for cleaning and disinfection of vehicles.
PROCESSING
Biosecurity during processing
Processing begins with the arrival at the abattoir. There are many points at which contamination can occur
pre-, during and post-slaughter and for this reason the HACCP (Hazard Analysis Critical Control Point)
system has been developed to ensure the safety of the final product (see below). Potential sources of
contamination include other animals, water, contaminated surfaces, personnel, and poor technique, for
instance allowing contents of the gastro-intestinal tract or abscesses to contaminate the meat. Ante-mortal
veterinary inspection of animals and meat inspection are critical to ensure that only healthy animals/healthy
meat enter the human food chain. Since waste disposal from abattoirs, including disposal of condemned
carcasses or meat, can be a source of infection or pollution, it must be carefully controlled.
HAZARD ANALYSIS CRITICAL POINTS (HACCP)
The system involves identifying hazards and instituting critical control points to eliminate them.
The principles of the system of hazard analysis and critical control points (HACCP) were introduced by the
Codex Alimentarius, a joint committee of the Food and Agriculture Organization of the United Nations and
the World Health Organization responsible for producing standards for food safety. They prescribe a certain
number of requirements:
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Biosecurity  Value chain for animal-derived food

identify any hazards that must be prevented, eliminated or reduced to acceptable levels;

identify the critical control points at the step or steps at which control is essential;

establish critical limits beyond which intervention is necessary;

establish and implement effective monitoring procedures at critical control points;

establish corrective actions when monitoring indicates that a critical control point is not under control;

implement own-check procedures to verify whether the measures adopted are working effectively;

keep records to demonstrate the effective application of these measures and to facilitate official controls
by the competent authority.
(Source: SCADPlus Summary of Regulation (EC) No 852/2004 of the European Parliament and of the
Council of 29 April 2004 on the hygiene of foodstuffs).
Codex lists 12 tasks to be undertaken in the application of HACCP:

Assemble the HACCP team

Describe the product

Identify intended use

Construct a flow diagram

On-site verification of flow diagram

List all potential hazards, conduct a hazard analysis, determine control measures

Determine critical control points

Establish critical limits for each critical control point

Establish a monitoring system for each critical control point

Establish corrective action for deviations that may occur


Establish verification procedures
Establish record keeping and documentation
There is no reason why this system should not be implemented throughout the value chain (i.e. also on farm)
in order to ensure a consistent approach to assurance of the final product.
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REFERENCES
1. Anon 2006 Principles of farm biosecurity. Technical Advice Sheet. British United Turkeys Ltd,
Tattenhall, UK
2. APHIS 2003 Biosecurity on US sheep operations. Info Sheet, Veterinary Services, Centers for
Epidemiology and Animal Health
3. APHIS 2006 Equine biosecurity and bio-containment practices on US equine operations. Info Sheet,
Veterinary Services, Centers for Epidemiology and Animal Health
4. APHIS 2009 Biosecurity on US beef cow-calf operations. Info Sheet, Veterinary Services, Centers
for Epidemiology and Animal Health
5. Arcadis 2010 Final Report: Assessment of the options to improve the management of bio-waste in
the European Union. Annex D: Industrial bio-waste. Study Contract No
07.0307/2008/517621/ETU/G4, European Commission DG Environment, ARCADIS Project No
11/004759 Version C 12-02-2010
http://ec.europa.eu/environment/waste/compost/pdf/ia_biowaste%20-%20final%20report.pdf
(accessed 26 September 2013)BAMN 2001 An introduction to infectious disease control on farms
(biosecurity). Bovine Alliance on Management and Nutrition (BAMN), AFIA Rich Sellers, Arlington,
VA, USA
6. BAMN 2001 Biosecurity on dairies. Bovine Alliance on Management and Nutrition (BAMN), AFIA
Rich Sellers, Arlington, VA, USA
7. Clift K 2010 Editorial - New approaches in biosecurity. Surveillance 37 (2): 3 – 4
8. Dee S, Deen J, Burns D, Douthit G, Pijoan C 2004 An assessment of sanitation protocols for
commercial transport vehicles contaminated with porcine reproductive and respiratory syndrome
virus. Canadian Journal of Veterinary Research 68: 208 – 214
9. Dee S, Torremorell M, Thompson B, Deen J, Pijoan C 2005 An evaluation of thermo-assisted drying
and decontamination for the elimination of porcine reproductive and respiratory syndrome virus from
contaminated livestock transport vehicles. Canadian Journal of Veterinary Research 69: 58 – 63
10. FAO/OIE/World Bank 2010 Good practices for biosecurity in the pig sector. Issues and options in
developing and transition countries. FAO Animal Production and Health Paper No 169, Food &
Agriculture Organization of the United Nations, Rome
11. FAO, 2011: A value chain approach to animal disease risk management – technical foundations and
practical framework for field application. Animal Production and Health Guidelines. No 4. Rome.
12. Patterson A, R, Baker R B, Madson D M, Pintar A L, Opriessnig T 2011 Disinfection protocols
reduce the amount of porcine circovirus type 2 in contaminated 1:61 scale model livestock transport
vehicles. Journal of Swine Health and Production 19: 156 - 164
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13. Pork Checkoff 2002 Biosecurity – Veterinarian in the war against foreign animal disease. National
Pork Board, Des Moines, Iowa
14. Pork Checkoff 2002 Security guide for pork producers. National Pork Board, Des Moines, Iowa
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Moines, Iowa
16. Rajkowski K, Eblen S, Laubauch C 1998 Efficacy of washing and sanitizing trailers used for swine
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